New Zealand's Prime Minister Jacinda Ardern has wrapped up a whirlwind official visit to Beijing, where she met with Chinese President Xi Jinping to shore up bilateral ties amid a spat over tech giant Huawei.

Key points:

China's Premier calls for New Zealand to ensure a fair investment environment

Ms Ardern raises the issue of China's treatment of Uyghur Muslims in Xinjiang

But Ms Ardern also raised the issue of China's treatment of Uyghurs and other Muslim minorities in its far-western Xinjiang region, where up to a million people are reportedly being held in so-called "re-education camps".

The visit comes two weeks after the Christchurch terror attack, which prompted a shortening of Ms Ardern's visit to a single day, meeting Mr Xi and Premier Li Keqiang.

"I did though want to visit Beijing at this time to underline the importance that we place on our relationship with China — it is one of our most important and far-reaching relationships," Ms Ardern said during the meetings.

Mr Xi called on New Zealand not to discriminate against Chinese companies during the meeting, seen by some as a reference to New Zealand's decision to effectively ban Huawei from it's 5G network last year.

"China is willing to continue to support strong companies to invest in New Zealand, and New Zealand should provide a fair, just, non-discriminatory operating environment for Chinese companies," a statement released by China's Foreign Ministry paraphrased Mr Xi as saying.

A spokesperson from the Foreign Ministry added during a briefing last night that "China and New Zealand need to advance bilateral economic and trade cooperation and make the pie bigger".

Ms Ardern didn't delve into specifics, but described the talks as "both warm and constructive" and said "New Zealand welcomes all high-quality foreign investment that will bring productive economic growth".

The situation in Xinjiang

China has been accused of targeting its Muslim minorities by operating a regime of repression and surveillance in Xinjiang, though Beijing has claimed its programs are all in the name of de-radicalisation.

While Ms Ardern received worldwide praise for showing solidarity with New Zealand's Muslim communities in the wake of the Christchurch attack, it appeared as though she was not making the same overtures when it came to the reported persecution of Chinese Muslims.

One journalist noted she appeared "reticent to lay the blame at China's feet" over repeated Uyghur claims of mistreatment.

"Not at all. I raised the issue directly with the Premier and with the President. You can't do much more than that," Ms Ardern said.

"No, absolutely not. I anticipated the issue as being of interest … and chose to proactively raise it," Ms Ardern said.

Equipment from the Chinese telecommunications giant was barred from New Zealand's future 5G mobile networks last year, following a decision from the country's Government Communications Security Bureau (GCSB).

This did not go down well in China, with one article in state media claiming Chinese tourists were "punishing" New Zealand in response to the decision, and Beijing also postponing a major China-New Zealand tourism initiative.

Ms Ardern backtracked on the move earlier this year, telling New Zealand media in February "there's been no final decision here yet" about Huawei's participation in any future 5G network.

Mr Li, without mentioning Huawei, called on New Zealand to ensure a fair investment environment.

"We hope that we can aspire to the greatest common denominator regarding each others' interests and that when each side's businesses invest in each other's businesses, they can enjoy a fair, transparent, convenient environment," he said.

"The New Zealand Government clearly thinks that there is foreign interference," said Anne-Marie Brady, a China expert from the University of Canterbury in New Zealand.

"The [Government] committee is forward-thinking, it's forward-looking, it's looking at legislative tweaks that may be necessary to make, or new legislation that we may require to make New Zealand more resilient."

While Ms Ardern did not discuss trade negotiation specifics, she said she was encouraged by ongoing trade talks.

"The language used today was very much around hastening the work, speeding up those negotiations. I took that to be very positive."